I am unclear on the issue of is this a "new" gun.

If the gun was shipped from S&W to the distributor, and then on to the dealer that sold it to the OP, I would consider it to be "new" and S&W is obligated to provide warranty service for however long it was when the gun was made back then.

If the gun was sold at retail and just never shot, it is used and no warranty would apply.

There is a difference between hoping that S&W will cover a claim that they are not legally obligated to in an effort to please a customer, and expecting that they must and then complaining when the letter of the warranty is followed.

Bob